Preheat the oven to 400°F degrees. Pierce the potatoes lightly with a fork or paring knife in a few spots all over the potatoes. Add them to a baking dish so they are in a single layer.

Add the olive oil, salt, and pepper. Toss with a spoon or hands until evenly coated. Cover with foil and bake until a fork inserted has no resistance. About an hour and a half.

When potatoes are done baking, let them sit on the counter until they are cool to the touch or at least 30 minutes.

Cut all of the potatoes in half lengthwise. With a small spoon, scoop out the insides of the potatoes and place them in a medium-sized bowl. Be careful to not tear the skin. Add in the sour cream, butter, and half of the cheese. Mash with a potato masher or the back of a fork until thoroughly combined and smooth. Taste and add salt and pepper if needed. Fill the potato skins with the mixture, place them filling side up onto a sheet tray and sprinkle the remaining parmesan on top.

Place them back into the oven for 15 minutes or until browned on top and heated through. If you would like them more brown on top, you can turn on the broiler for a few minutes to get them extra toasty and delicious.

Serve with a small dollop of sour cream and chives on top of each potato.